UV emitting spicules
Abstract
EUV observations of spicules in the solar chromospheric network are discussed. Spectroheliograms each produced at seven wavelengths were acquired by the EUV Harvard spectrometer on board Skylab. Analysis of the frequency vs. intensity distribution of chromospheric and transition region lines of ions formed in different temperature regions indicates a network area percentage on the order of 40%, with approximately 1500 spicules in each spectroheliogram. If it is assumed that the network consists of evenly spaced spicules along the supergranular boundaries, then the average intensities derived from the frequency vs. intensity distribution would be representative of spicule emission and could be used to give an upper limit to the values of the differential emission measure. If, on the other hand, the spicules are assumed to be clumped together, the average intensities of the spicules could be derived from those of the brightest network elements and would provide a lower limit to the differential emission measure. Data is consistent with the UV spicules being H alpha spicules falling back after heating, and leads to an estimate of 2 x 10 to the 10th/cu cm for the average density of the spicules.
- Publication:
-
Solar and Interplanetary Dynamics
- Pub Date:
- 1980
- Bibcode:
- 1980IAUS...91..199P
- Keywords:
-
- Extreme Ultraviolet Radiation;
- Solar Atmosphere;
- Solar Radiation;
- Spicules;
- Chromosphere;
- H Alpha Line;
- Skylab Program;
- Solar Spectrometers;
- Solar Physics